There exist programmable signaling mechanisms, such as the Smart Siren(copyright) system marketed by Federal Signal Corporation, and disclosed in U.S. Pat. No. 5,296,840. The Smart Siren(copyright) system allows a user to selectively program desired signaling features, such as various lights and sirens, to activate in each of a number of user selectable modes. For instance, a user may use the Smart Siren(copyright) system keypad to program the vehicle""s flashing lights to activate in a first mode, whereas in a second mode, additional lights are activated and in a third mode a siren is activated. In the Smart Siren(copyright), a slide switch is provided to allow the user to quickly switch between modes. In addition to programming the desired signaling in each mode, the nature of the siren tone is also programmable through the same input keypad. For example, the siren tone may be programmed to be a yelp, wail, or air horn sound. Because of this programmability, this system has greatly reduced the workload on operators of emergency vehicles.
It is also known to provide a load shedding device to manage electrical loads in a vehicle. Existing load shedding devices may be placed in a vehicle and appropriately configured via dip switches or otherwise to provide a desired load shedding function. For example, such a device may measure vehicle battery voltage, and sequentially disable electrical loads, such as various lights, until the vehicle charging system is able to meet the electrical demands of the vehicle.
Users of emergency vehicles may desire to have both a smart signaling system such as the Smart Siren(copyright) and load shedding functionality on one vehicle. In such cases, the user has traditionally had to install two separate systems and user inputs. For example, a dash-mounted console is installed to operate the Smart Siren(copyright) system, while an additional dash-mounted console is required for the load manager. In addition, the load manager relay board must also be installed in the vehicle. These two systems are completely independent, must operate independently, and are independently programmed. This creates difficulties for users in that programming of both systems takes more time and is more complex due to the necessity of interacting with multiple user inputs. In addition, redundancy of parts, functions, and wiring in the two systems causes the price of such separate systems to be prohibitive for many applications. Also, the overall reliability and performance of such a system is compromised due to the complex wiring schemes involved in the installation.
An emergency signaling device is needed whereby the load managed enabling and disabling of external functionality, such as lights, and the provision of specific signal content, such as siren tone, are provided centrally through a consistent interface in a user-friendly and cost-effective manner.
The present invention solves the problems associated with the prior art by providing an integrated programmable siren control system and programmable load management system for use in emergency vehicles, wherein the integrated system may operate in either a programming or operating mode. The integrated system includes a control head with keypad, and a control unit. In the operating mode, portions of the keypad are usable to selectively enable various signaling devices.
The load management feature automatically causes the shedding of electrical loads in a pre-programmed sequential manner when it detects that the vehicle battery voltage is lower than certain threshold levels, and that the vehicle is in a PARK condition. This ensures that more critical electrical systems, such as vehicle engine ignition and radio functionality, remain uncompromised. The integrated functions are programmable from a centralized location readily accessible to the vehicle operator, avoiding the need to control functions from separate locations through separate user inputs.
In addition to managing these relay outputs, the load manager also controls the fast idle of the vehicle in low-battery situations as an initial attempt to prevent draining of the battery by the loads of the emergency system. Loads are shed in response to a low-battery-voltage condition if the fast idle condition does not stop the deterioration of the battery voltage. An audible beep may be generated each time a load is turned off. All previously shed loads will be restored at 0.5 seconds interval with reversed sequence as they were shed when the vehicle shifts out of PARK.
Battery voltages above the reference point will not restore previously shed loads. Only after the PARK has been released and engaged again will the load manager be reset. This portion of the load manager for a specific load can also be turned off through programming to prevent load shedding under certain operational conditions.
As soon as the vehicle shifts out of PARK, the HIGH IDLE output will be turned off immediately. HIGH IDLE will also be turned off if the battery voltage returns to a user-programmable point above the reference voltage (e.g. 13.8V).
Other objects and advantages will become apparent upon reference to the following detailed description when taken in conjunction with the drawings.
While the invention will be described in connection with a preferred embodiment, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications, and equivalents falling within the spirit and scope of the invention as defined by the appended claims.